Radiotherapy is a proven modality for cancer cure similar to surgery for tumors of all sites. The probability to destroy the cancer locally is proportional to the radiation dose delivered to the cancer sites. Most often, the effectiveness of radiotherapy is limited by the radiation dose that can safely be delivered to the normal organs adjacent to the tumor. Serious complications may occur if the normal organs receive a radiation dose that exceeds their tolerance to radiation. Paralysis (spinal cord injury), blindness (optic nerve injury), stroke (brain injury), bleeding (blood vessels injury), inflammation of lungs (lungs injury) and bowels (bowels injury) may lead to death or seriously affect patient quality of life are well known complications of radiation treatment.
As such, prescribed doses are established in the literature to limit toxicity of the treatment to avoid complications. For example, Section 6.4.2.4 Radiation Therapy Oncology Group (RTOG) study number 0225: A Phase II Study of Intensity Modulated Radiation Therapy (IMRT)+/Chemotherapy for Nasopharyngeal Cancer specifies that “No more than 20% of any PTV70 (the gross tumor volume with a 5 mm margin) will receive ≧110% of the prescribed dose.” As used herein, the term “prescribed dose” means the conventional dose established in the literature for cancer cure with external beam radiotherapy alone or combined with chemotherapy for locally advanced head and neck cancer. As non-limiting examples, the “prescribed dose” for Oropharyngeal cancer, Oral cavity cancer, Laryngeal cancer, Hypopharyngeal cancer is about 7000 cGy, at about 200 cGy per day.
The present invention features an image-guided radiotherapy system for tumor treatment, wherein a boosted radiation dose is applied to a boost region within a tumor boundary.
Any feature or combination of features described herein are included within the scope of the present invention provided that the features included in any such combination are not mutually inconsistent as will be apparent from the context, this specification, and the knowledge of one of ordinary skill in the art. Additional advantages and aspects of the present invention are apparent in the following detailed description and claims.